Treatment of hydrocarbons



Patented May 4, 1943 TREATMENT OF HYDROCARBONS Warren W. Johnstone, Chicago, 111., assignor to Universal Oil Products Company, Chicago, 111., a corporation of Delaware No Drawing. Application July 26, 1941, Serial No. 404,153

8 Claims.

This invention relates to a method for treating hydrocarbon oil to remove objectionable sulfur compounds therefrom. More particularly, it relates to a process for removing mercaptan sulfur compounds from hydrocarbon oils by means of an improved alkaline treating agent.

In one specific embodiment the present invention comprises a method for reducing the mercaptan content of hydrocarbon oils by treating said oils in the presence of solutions of alkali metal hydroxides containing nitro-paramns.

The eflect of the nitro-parafiins appears to be to increase the solubility of mercaptans in the alkaline solutions.

The treatment is normally carried out at atmospheric conditions of temperature and pressure although slightly superatmospheric or subatmospheric pressures may be employed to advantage in some instances. Moreover, when treating hydrocarbons which are normally gaseous at the treating temperature used, it is usually desirable to apply sufilcient pressure to maintain the hydrocarbon in the liquid phase. Any type of treating apparatus may be used. The greatest benefit is obtained, however, when using a countercurrent type of flow, either in single or multiple stages of contacting, whereby the partially treated gasoline is continuously being contacted with fresh treating agent which has been used to a relatively slight extent. These methods of contacting are Well known and need not be described in detail.

Any alkali metal hydroxide may be used although sodium and potassium hydroxides are the most readily available and appear to give the best results.

The treating solution may be made up by dissolving alkali metal hydroxide in Water and adding the nitro-paraffin to the solution. The amount of nitro-parafiin added may vary considerably. Solutions containing about 51-50% by weight of nitro-parafiln have been found to be satisfactory, the remainder of the solution being composed of the alkali metal hydroxide and water. Satisfactory solutions may be made containing approximately 150% by weight of alkali metal hydroxide although the usual concentration is of the order of 5-15% by weight. The quantity of water present depends upon the amount of nitro-parafiin and alkali metal hydroxide used.

The exact composition of the solution for use with a given oil can not be foretold exactly since a wide variety of oils may be treated and the different nitro-parafiins and alkali metal hydroxides may have somewhat different degrees of effectiveness when used in conjunction with different oils. Mixtures of nitro-paraflins may also be used. In some instances it is desirable to use other solvents as well as water, for example alcohols, polyhydroxy alcohols, phenols, etc., to assist in removing the mercaptan sulfur. Such additional solvents must be miscible with the Example 1 A West Texas cracked gasoline containing 0.043% mercaptan sulfur was treated with 10% by volume of 6 N aqueous potassium-hydroxide solution, the mercaptan contentbeing reduced to 0.008%. When this same gasoline was treated with 10% by volume of a solution containing potassium hydroxide (6 N) and nitro-methane (3 N) the mercaptan content was reduced to 0.005%.

Example 2 When the gasoline used in Example 1 was treated with 10% by volume of a solution consisting of 6 N potassium hydroxideand 3 N nitropropane, the mercaptan content less than 0.001%.

I claim as my invention:

1. A method for refining a hydrocarbon oil to reduce the sulfur content thereof, which comprises treating said hydrocarbon oil with an alkali metal hydroxide solution containing 2. nitroparaflin.

2. A method for refining hydrocarbon oil to remove sulfur therefrom, which comprises treating said oil with an alkali metal hydroxide solution containing nitro-propane.

3. A method for refining hydrocarbon. oil to remove sulfur therefrom, which comprises treating said oil with an alkali metal hydroxide solution containing nitro-methane.

4. A method for refining hydrocarbon oil to remove sulfur therefrom, which comprises treatwas reduced to move sulfur therefrom, which comprises treating said oil with an aqueous solution of an alkali metal hydroxide containing a nitro-paraflin.

8. A process for refining hydrocarbons containing mercaptans which comprises treating the hydrocarbons with an alkali metal hydroxide solution containing a nitro-parafiin capable of increasing the solubility of mercaptans in the hydroxide solution.

WARREN W. J OHNSTONE. 

